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NMR Calculations with Quantum Methods: Development of New Tools for Structural Elucidation and Beyond
Maribel O Marcarino1, Marı A M Zanardi2, Soledad Cicetti1
1Instituto de Quı́mica Rosario (CONICET), Facultad de Ciencias Bioquı́micas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, Argentina.
Accounts of Chemical Research
|August 16, 2020
Summary
Quantum NMR calculations aid in organic molecule structure elucidation. New AI and computational methods like DP4+ improve accuracy, overcoming challenges in complex systems for reliable structural validation.
Area of Science:
- Computational Chemistry
- Organic Chemistry
- Spectroscopy
Background:
- Structural elucidation of organic molecules is crucial but challenging.
- NMR spectroscopy is the primary technique, yet misinterpretations are common.
- X-ray crystallography is definitive but limited by crystal availability.
Purpose of the Study:
- To describe investigations in quantum NMR calculations for structural elucidation.
- To highlight the development of AI-driven tools and computational methods.
- To showcase practical applications in validating and revising molecular structures.
Main Methods:
- Development and application of artificial neural networks (ANNs) for structural validation.
- Implementation of DP4+ and J-DP4 methods for probabilistic structure determination.
- Utilizing quantum chemical calculations (DFT) for NMR chemical shifts and coupling constants.
Main Results:
- ANNs demonstrated high accuracy in identifying connectivity and stereochemical errors.
- DP4+ and J-DP4 methods successfully assigned structures for challenging motifs.
- Computational tools aided in revising misassigned natural product structures, some validated by synthesis.
Conclusions:
- Quantum NMR calculations, enhanced by AI and advanced computational methods, are powerful tools for structural elucidation.
- These methods address limitations of experimental techniques and improve the reliability of published structures.
- Ongoing research aims to tackle complex systems, such as those with extensive hydrogen bonding, using novel computational approaches.
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